The invention relates to a disk brake of a motor vehicle. The object of the invention is to improve the braking performance of disk brakes while reducing the manufacturing cost of such disk brakes. The invention is more particularly intended for the automotive sector but could also be applied in other sectors.
A disk brake of a vehicle is usually situated on a hub of at least one wheel of the vehicle which hub receives an axle of the vehicle wheel and supports the disk brake. A disk brake is connected to the wheel of the vehicle in such a way that the wheel imparts a rotational movement to the brake disk.
The disk brake comprises a caliper forming a first jaw and a second jaw, the first jaw and the second jaw facing one another on either side of a plane of a brake disk and joining together outside the disk. The first jaw and the second jaw of the caliper are provided with a first brake pad and with a second brake pad, respectively. The brake pads are placed facing one another, on either side of the brake disk, in such a way that their plane of symmetry is coplanar. This caliper is intended to apply the first brake pad and the second brake pad via the first jaw and the second jaw, respectively, against a first face and against a second opposed face of a brake disk. A disk brake also comprises a carrier fixed to the hub of at least one wheel of the vehicle. The carrier supports the caliper and at least partially flanks each brake pad longitudinally with respect to a direction of the rotational movement of the brake disk.
During braking, the first brake pad and the second brake pad draw together perpendicularly with respect to a plane of the brake disk via the first jaw and via the second jaw. In order to draw together perpendicularly to the plane of the brake disk, at least one of the brake pads is first pushed toward the brake disk via a piston placed in at least one of the jaws of the caliper. The piston exerts a pressure, for example on the first brake pad, such that the piston tends to draw the first brake pad against the brake disk perpendicularly to the plane of this same brake disk. This piston moves under the action of at least one braking circuit generating a hydraulic pressure on the piston. The braking circuit may comprise a master cylinder of a vehicle, for example. The second brake pad is then directed perpendicularly toward the brake disk by a reaction of the other jaw moving in return toward the disk.
The carrier allows the caliper to be maintained straddling the disk. By straddling is meant the fact that the caliper is placed of either side of the plane of the disk while passing over the disk, outside a periphery of the disk. The carrier also allows the caliper to be guided during advancing/retreating movements of this same caliper with respect to the disk. The advancing movements of the caliper are produced during vehicle braking, causing the pads to be drawn together against the disk. The retreating movements of the caliper are produced during vehicle braking disengagement, causing the pads to be separated with respect to the disk.
To maintain the caliper in a straddling orientation and to guide the caliper, it is known for the carrier to have bores intended to receive guide pins carried by the caliper, the pins and the bores cooperating to produce the advancing/retreating movements of the caliper with respect to the disk. These pins allow the caliper to be supported by the carrier while facilitating the guiding of the two pads against the disk. The carrier extends above the disk with its bores so that the pins slide in these bores while also passing over the disk. The carrier keeps the two pads in position and it recovers the major part of the braking torque.
Document FR 2 747 751 describes a brake disk provided with a carrier and with a caliper. This document describes that the two guide pins are carried by the carrier and that the bores are formed in the caliper. These guide pins are each arranged with an axis parallel to a central axis of the disk. More specifically, these pins are arranged with one having an axis passing beyond the periphery of the disk and extending on either side of the disk and with the other having an axis passing inside this same periphery, the second pin extending on only one side of the disk. This specific arrangement of the axes of the pins makes it possible to substantially reduce the distance between these two axes, thereby resulting in minimum frictional torque. Jamming of the pins is thus minimized, and sliding can take place under optimum conditions.
However, this type of disk brake has the disadvantage of having a considerable weight. The braking performance is all the more reduced as a result.